Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adopt	Common Stock	Preferred Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adopt
Balance at beginning of period at Dec. 31, 2018	$ 11,659		$ 0	$ 0	$ 8,058	$ (1,066)	$ 4,667
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,567						1,567
Other comprehensive income (loss)	(53)					(53)
Stock based compensation	43				43
Dividends paid (Note 11)	(445)						(445)
Dividends declared on preferred stock (Note 11)	(45)						(45)
Balance at end of period at Dec. 31, 2019	12,726	$ (643)	0	0	8,101	(1,119)	5,744	$ (643)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,009						2,009
Other comprehensive income (loss)	(190)					(190)
Stock based compensation	49				49
Issuance of preferred stock	492				492
Dividends paid (Note 11)	(845)						(845)
Balance at end of period at Dec. 31, 2020	13,598		0	0	8,642	(1,309)	6,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,789						3,789
Other comprehensive income (loss)	36					36
Stock based compensation	50				50
Dividends paid (Note 11)	(3,620)						(3,620)
Dividends declared on preferred stock (Note 11)	(59)						(59)
Balance at end of period at Dec. 31, 2021	$ 13,794		$ 0	$ 0	$ 8,692	$ (1,273)	$ 6,375